async def subscribe_async_iterator_mock():
# Create an AsyncIterator from an EventEmitter
emitter = EventEmitter()
iterator = EventEmitterAsyncIterator(emitter, "publish")
# Make sure it works as an async iterator
assert iterator.__aiter__() is iterator
assert callable(iterator.__anext__)
# Queue up publishes
assert emitter.emit("publish", "Apple") is True
assert emitter.emit("publish", "Banana") is True
# Read payloads
assert await iterator.__anext__() == "Apple"
assert await iterator.__anext__() == "Banana"
# Read ahead
i3 = iterator.__anext__()
i4 = iterator.__anext__()
# Publish
assert emitter.emit("publish", "Coconut") is True
assert emitter.emit("publish", "Durian") is True
# Await results
assert await i3 == "Coconut"
assert await i4 == "Durian"
# Read ahead
i5 = iterator.__anext__()
# Terminate emitter
await iterator.aclose()
# Publish is not caught after terminate
assert emitter.emit("publish", "Fig") is False
# Find that cancelled read-ahead got a "done" result
with raises(StopAsyncIteration):
await i5
# And next returns empty completion value
with raises(StopAsyncIteration):
await iterator.__anext__()
async def subscribe_async_iterator_mock():
# Create an AsyncIterator from an EventEmitter
emitter = EventEmitter()
iterator = EventEmitterAsyncIterator(emitter, 'publish')
# Queue up publishes
assert emitter.emit('publish', 'Apple') is True
assert emitter.emit('publish', 'Banana') is True
# Read payloads
assert await iterator.__anext__() == 'Apple'
assert await iterator.__anext__() == 'Banana'
# Read ahead
i3 = iterator.__anext__()
i4 = iterator.__anext__()
# Publish
assert emitter.emit('publish', 'Coconut') is True
assert emitter.emit('publish', 'Durian') is True
# Await results
assert await i3 == 'Coconut'
assert await i4 == 'Durian'
# Read ahead
i5 = iterator.__anext__()
# Terminate emitter
await iterator.aclose()
# Publish is not caught after terminate
assert emitter.emit('publish', 'Fig') is False
# Find that cancelled read-ahead got a "done" result
with raises(StopAsyncIteration):
await i5
# And next returns empty completion value
with raises(StopAsyncIteration):
await iterator.__anext__()